^what's the idle rpm you keep ? Last time I got my bike serviced, the mechanic tuned it upto ~2k rpm. Mileage drastically went down from 35 to 20. (I own RTR 160). Then I got it decreased to ~1.1 or so. Is it ok? and what are the other two screws (except AFR) for ?
My Idle rpm is around 1k rpm for a cold started engine, and 1.5k for a heated up engine (by heated up I mean, when its daytime and you have run it for 5-10 kms). Its ideal according to manuals.
The other two screws on the lower part? They are for opening the carburetor's lower column, and replacing the "MAIN JET". Fuel supply should be off when you open this cover.
Actually, if you have to make major changes to the AFR (specially when you install a modification component, like K&N air filter, performance exhaust, etc.) then you have to change the main jet to a bigger holed one. I have changed the main jet on my Pulsar 208 to get its AFR right.
AFR screw can only make minor to medium difference to your Air Fuel Ratio, not major. Hence, Main jet had to be changed to a bigger one.
^^Its less than 2k and grater than 1 k that you should keep. 1.5k
@ Samarth 619
Thanku thanku thanku very much. You know the picture you posted is the only picture over the internet about how to tune Pulsar. I was searching for it for 2 years.
Hey I solved my problem today. I found that my battery is dry completely. So put acid and water. Also air filter was very dirty, so cleaned it. My bike is back to form.
And I dont see any coloured smoke. Spark plug had dark residue, so more oil, less air right ? lets see few days since I cleaned air filter today.
And how should I turn the AFR, clockwise or anticlockwise ? And since it was before not starting at kick, should battery really can be the problem ? ANd another question is whenever I start my bike after a long rest, like in morning, my RPM touches 4k-5k without even acceleration. It stays like that for a few minutes and then comes to idle RPM. Is it normal ?
and give me sometime, I will tighten the AFR, I have holiday on 13th
Acid and Water? Well, I suggest that when your battery expires, get a maintenance free battery. I got an Amaron with a 5 year warranty, for Rs. 1600 few years back and so far, it has never given me a problem. Even a wired battery recharge was not needed, as the battery never became weak. It works like a charm.
As for the pic, I snapped it myself on my own pulsar and uploaded it on my imageshack a/c. I had to make this pic for helping someone at Xbhp, a biking site where I'm a junior moderator.
And, when your rpm raises itself only on the morning starts, it could most probably mean that your bike has autochoke, and it is working normally.
Just for your knowledge, twisting the AFR screw:
* Clockwise- will tighten it and make it run lean (lesser fuel : more air),
* Anti clockwise- will open the screw, make it richer (more fuel : less air).
Carb tuning is a complicated process, don't hurry it. My Pulsar 208 gives me a mileage of around 40 kmpl with hard riding & good throttle response and one button starts in the morning. That was achieved, when I tuned it according to a certain procedure for 5-6 days after I modified it.
I suggest that you don't twist the AFR screw yourself right now, or make very minimal adjustments only, like upto half a circle turn clockwise (since you said spark plug shows black residue). Just observe your bike for some days, and try checking its performance & engine temperature...